Composite-type ruler

Abstract

A square is usable in association with a tape ruler. The square includes a ruler member as a base bar and a transverse longitudinal member formed at one side of the ruler member. An arc member is formed at the other side of the ruler member. A pair of guides are provided at the front and back surfaces of the ruler member. Each guide has two guiding grooves for receiving a respective tape ruler of different width. A permanent magnet is buried in each guide in order to maintain engagement between the guide and the tape ruler when the square is slid along the tape ruler.

What is claimed is: 
     
       1. A square comprising a ruler member having a front surface and a back surface and two edges extending along both of said front surface and said back surface,   a longitudinal member integrally formed with one end of said ruler member at one edge of said ruler member and provided with upper and lower edges each forming a right angle with respect to said one edge of said ruler member,   an arc member integrally formed with said one end of said ruler member at the other edge of said ruler member and provided with an outer semi-circular edge and an inner, inclined straight edge forming an angle of 45° with respect to said other edge of said ruler member,   a guide provided at each of said front surface and said back surface of said ruler member, said guide having two guiding grooves for receiving respective tape rulers with different widths, said grooves each having a width and cross-sectional shape corresponding to those of the tape rulers, and   a permanent magnet buried in said guide and adapted to maintain an engagement between said guide and the tape ruler.   
     
     
       2. A square according to claim 1, further comprising a step formed on said inclined edge of said arc member at each of a front surface and a back surface of said arc member and extended along a line aligned with said lower edge of said longitudinal member, and a step formed on said other edge of said ruler member adjacent said inclined edge of said arc member at each surface of said ruler member and positioned near a corner defined by said other edge of said ruler member and said inclined edge of said arc member, said step forming a right angle with respect to said inclined edge of said arc member. 
     
     
       3. A square according to the claim 1, wherein said longitudinal member and said arc member each are provided with a level and a pair of openings for exposing said level.